[PATCH 1/5] perf trace: Validate syscall id before growing syscall table

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

In some cases the ID for a syscall read thru the raw_syscalls tracepoint
is bogus, still needs to be investigated why, but to make the tool more
robust first try to resolve the ID to a name via libaudit and if it
fails, don't grow the table.

Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-0lsokw3xor7c4ijo45u6bauh@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-trace.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index dec8ced..83c6515 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -56,6 +56,10 @@ static int trace__read_syscall_info(struct trace *trace, int id)
 {
 	char tp_name[128];
 	struct syscall *sc;
+	const char *name = audit_syscall_to_name(id, trace->audit_machine);
+
+	if (name == NULL)
+		return -1;
 
 	if (id > trace->syscalls.max) {
 		struct syscall *nsyscalls = realloc(trace->syscalls.table, (id + 1) * sizeof(*sc));
@@ -75,11 +79,8 @@ static int trace__read_syscall_info(struct trace *trace, int id)
 	}
 
 	sc = trace->syscalls.table + id;
-	sc->name = audit_syscall_to_name(id, trace->audit_machine);
-	if (sc->name == NULL)
-		return -1;
-
-	sc->fmt = syscall_fmt__find(sc->name);
+	sc->name = name;
+	sc->fmt  = syscall_fmt__find(sc->name);
 
 	snprintf(tp_name, sizeof(tp_name), "sys_enter_%s", sc->name);
 	sc->tp_format = event_format__new("syscalls", tp_name);
-- 
1.7.1

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